Typical eh? They don't mind taking your custom, but not in too much of a hurry to resiprocate!
I bought a DVD in Tesco last week & had a voucher in my bag reading ' Use this voucher before the 28 Feb to gain an extra 500 points, when buying any DVD. I forgot to hand over the voucher, so went in the next day, only to be told "You should have handed it in on the day of purchase".
I asked them to show me on the voucher or reciept where it said that, but they couldn't! I asked if they could make a special consession because of this, but they wouldn't budge.
I walked out in disgust saying I'd email Head Office, but I couldn't be botthered. I just won't buy any more DVD's in there again - so they're the ones losing out!